SOLUTION: At a thrift store, each shirt costs $4, each pair of pants costs $7, and there is no sales tax on clothing purchases. Jason bought some shirts and some pairs of pants at the thrift

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: At a thrift store, each shirt costs $4, each pair of pants costs $7, and there is no sales tax on clothing purchases. Jason bought some shirts and some pairs of pants at the thrift      Log On


   



Question 1109749: At a thrift store, each shirt costs $4, each pair of pants costs $7, and there is no sales tax on clothing purchases. Jason bought some shirts and some pairs of pants at the thrift store and paid exactly $41. How many shirts and how many pairs of pants did Jason buy at the thrift store?

Found 2 solutions by greenestamps, josmiceli:
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


If x is the number of shirts and y is the number of pairs of pants, then

4x%2B7y+=+41

You can solve this using formal algebra and the fact that x and y have to be whole numbers. However, since the numbers are small, it is much faster to solve the problem by logical reasoning and a bit of trial and error.

You know the total spent is an odd number; the cost of a shirt is an even number and the cost of a pair of pants is an odd number. Logic tells you then that the number of pairs of pants must be odd. So

1 pair of pants = $7; $41-$7 = $34; but 34 is not divisible by 4.

3 pairs of pants = $21; $41-21 = $20; 20/4 = 5.

So he bought 3 pairs of pants and 5 shirts.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = number of shirts bought
Let +b+ = number of pairs of pants bought
-----------------------------------------
+4a+%2B+7b+=+41+
There are 2 unknowns but only 1 equation, so I
have to use trial and error
----------------------------
shirts - - - - - - pants - - - - - - total cost
0 - - - - - - - - 6 - - - - - - - - 42
1 - - - - - - - - 5 - - - - - - - - - 39
2 - - - - - - - - 5 - - - - - - - - - 43
3 - - - - - - - - 4 - -- - - - - - - 40
5 - - - - - - - - 3 - - - - - - - - - 41
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He bought 5 shirts and 3 pairs of pants